基于Wheeler's Conforming Mapping扩展变换法的聚合物电光调制器特性研究

基于Wheeler变换模型,提出了一种分析多层介质微波特征参数的方法--Wheeler's Conforming Mapping扩展变换法,并利用该方法得到了微波特征参数与各层介质参数之间的表达式,在此基础上分析了微带电极的微波特性参数. 与准静态有限元法(QS-FEM)相比,Wheeler's Conforming Mapping扩展变换法不仅计算准确而且具有更高的计算效率. 将该方法应用于聚合物电光调制器的特性研究,对传统模型进行改进,通过添加补偿层来调整微波等效折射率和特征阻抗,改善微波与光波有效折射率的失配度,在理论上实现了聚合物电光调制器的速率和阻抗的同时匹配. 关键词： Wheeler扩展变换法 微带电极 特征参数 等效介电常数     

连花清瘟胶囊中6种有效成分的毛细管胶束电动色谱法测定

建立了毛细管胶束电动色谱法同时测定中药复方制剂连花清瘟胶囊中甘草苷、芦丁、金丝桃苷、槲皮苷、绿原酸、大黄酸6种药效成分含量的分析方法.使用未涂层弹性石英毛细管,以50 mmol/L SDS-15mmol/L磷酸氢二钠-15 mmol/L硼酸(含25%异丙醇,pH=8.0)作电解质,于254 nm下紫外检测,被测组分在3...     

一维矩形刻槽相位栅的减反特性与结构优化

 为了得到一种结构简单、便于制作的可应用于可见光波段的减反射膜,利用等效介质理论研究了表面具有矩形刻槽周期分布形式的介质膜的减反射特性,比较了4种不同基底材料的减反特性,选用聚甲基丙烯酸甲酯（PMMA）作为基底分析了一维单层矩形光栅结构的减反射膜的占空比、蚀刻深度、入射波长和入射角度对减反射特性的影响;给出了可见光波段的减反射膜的结构设计参数。研究结果表明：当入射角小于30°时,可见光中的短波段（0.4 μm～0.55 μm）反射率低于2%;当入射角小于10°时,该减反射膜可以使0.4 μm～0.8 μm可见光的反射率低于2%。     

A new effective potential for deuteron

We calculate for the first time the static properties of the deuteron, within the framework of supersymmetric quantum mechanics, analytically. A new effective potential and its partner are derived from a superpotential so that all parameters are fitted by the experimental data. An analytical expression is obtained for the deuteron wave function and contributions of the orthogonal ¹³S₁ and ¹³D₁ states are determined, explicitly. Compared to one pion exchange, the superpotential produces an electrostatic as well as two pion exchange terms for the potential. The saddle point radius of the potential and the maximum of the wave function are linearly proportional. In comparison with other methods, the approach presented in this paper is a new and extensible symmetry-based approach that, despite its straightforward calculations and explicit analytical expressions, provides a good explanation for two-body effective interactions such as two-nucleon systems and diatomic molecules.     

The effective hydrodynamic radius in the Stokes–Einstein relation is not a constant

Variants based on the assumption of effective hydrodynamic radius being a constant are usually adopted to test the Stokes–Einstein (SE) relation. The rationality of the assumption is examined by performing molecular dynamics simulations with the truncated Lennard-Jones-like (TLJ) model, Kob–Andersen model and ortho-terphenyl (OTP) model. The results indicate the assumption is generally not established except for special case. The effective hydrodynamic radius is observed to increase with decreasing temperature for TLJ model but is decreased for Kob–Andersen and OTP model; and which is almost a constant for TLJ particle with enough rigidity. The variant of SE relation $D\sim T/\eta $ is invalid for the three models except for the TLJ particle with enough rigidity. We propose similar inconsistency may be also existed in other liquids and the assumption should be critically evaluated when adopted to test the SE relation.     

Escape rate of an active Brownian particle in a rough potential

We discuss the escape problem with the consideration of both the activity of particles and the roughness of potentials. We derive analytic expressions for the escape rate of an active Brownian particle in two types of rough potentials by employing the effective equilibrium approach and the Zwanzig method. We find that activity enhances the escape rate, but both the oscillating perturbation and the random amplitude hinder escaping.     

Open charm mesons and charmonia in magnetized strange hadronic matter

We investigate the in-medium masses of open charm mesons (D(\begin{document}$ D^0 $\end{document}, \begin{document}$ D^+ $\end{document}), \begin{document}$ \bar{D} $\end{document}(\begin{document}$ \bar{D^0} $\end{document}, \begin{document}$ D^- $\end{document}), \begin{document}$ D_s $\end{document}(\begin{document}$ {D_{s}}^+ $\end{document}, \begin{document}$ {D_{s}}^- $\end{document})) and charmonium states (\begin{document}$ J/\psi $\end{document}, \begin{document}$ \psi(3686) $\end{document}, \begin{document}$ \psi(3770) $\end{document}, \begin{document}$ \chi_{c0} $\end{document}, \begin{document}$ \chi_{c2} $\end{document}) in strongly magnetized isospin asymmetric strange hadronic matter using a chiral effective model. In the presence of a magnetic field, the number and scalar densities of charged baryons have contributions from Landau energy levels. The mass modifications of open charm mesons result from their interactions with nucleons, hyperons, and the scalar fields (the non-strange field σ, strange field ζ, and isovector field δ) in the presence of a magnetic field. The mass modifications of the charmonium states result from the modification of gluon condensates in a medium simulated by the variation in the dilaton field (χ) in the chiral effective model. The effects of finite quark masses are also incorporated in the trace of the energy-momentum tensor in quantum chromodynamics to investigate the mass shifts of charmonium states. The in-medium masses of open charm mesons and charmonia are observed to decrease with an increase in baryon density. The charged \begin{document}$ D^+ $\end{document}, \begin{document}$ D^- $\end{document}, \begin{document}$ {D_{s}}^+ $\end{document}, and \begin{document}$ {D_{s}}^- $\end{document} mesons have additional positive mass shifts due to Landau quantization in the presence of a magnetic field. The effects of the strangeness fraction are observed to be more dominant for \begin{document}$ \bar{D} $\end{document} mesons compared with D mesons. The mass shifts of charmonia are observed to be larger in hyperonic media compared with nuclear media when the effect of the finite quark mass term is neglected. These medium mass modifications can have observable consequences on the production of the open charm mesons and charmonia in high-energy asymmetric heavy-ion collision experiments.     

Excitonically renormalised coupled-cluster theory

A variant of coupled-cluster theory is described here, wherein the degrees of freedom are fluctuations of fragments between internally correlated states. The effects of intra-fragment correlation on the inter-fragment interaction are pre-computed and permanently folded into an effective Hamiltonian, thus avoiding redundant evaluations of local relaxations associated with coupled fluctuations. A companion article shows that a low-scaling step may be used to cast the electronic Hamiltonians of real systems into the form required. Two proof-of-principle demonstrations are presented here for non-covalent interactions. One uses harmonic oscillators, for which accuracy and algorithm structure can be carefully controlled in comparisons. The other uses small electronic systems (Be atoms) to demonstrate compelling accuracy and efficiency, also when inter-fragment electron exchange and charge transfer must be handled. Since the cost of the global calculation does not depend directly on the correlation models used for the fragments, this should provide a way to incorporate difficult electronic structure problems into large systems. This framework opens a promising path for building tunable, systematically improvable methods to capture properties of systems interacting with a large number of other systems. The extension to excited states is also straightforward.     

Quantum lifetimes and momentum relaxation of electrons and holes in Ga0.7In0.3N0.015As0.985/GaAs quantum wells

Electronic transport in n- and p-type modulation-doped Ga_0.7In_0.3N_0.015As_0.985/GaAs quantum wells are investigated using magneto-transport measurements in the temperature range between T?=?1.8 and 32?K and at magnetic fields up to B?=?11?T. The momentum relaxation and the quantum lifetimes (τ_q ) of electrons and holes are obtained directly from the temperature and magnetic field dependencies of the SdH oscillation amplitudes, respectively. A detailed analysis of quantum and transport life times indicates that the momentum relaxation of holes is forward displaced in k-space, while a large angle-scattering mechanism is prominent for the electrons. This discrepancy is believed to be due to scattering of electrons with nitrogen complexes and to the lack of such a mechanism for holes.     

Macroscopic constitutive equations of thermo-poroelasticity derived using eigenstrain–eigenstress approaches

Macroscopic constitutive equations for thermoelastic processes in a fluid-saturated porous medium are re-derived using the notion of eigenstrain or, equivalently, eigenstress. The eigenstrain-stress approach is frequently used in micromechanics of solid multi-phase materials, such as composites. Simple derivations of the stress–strain constitutive relations and the void occupancy relationship are presented for both fully saturated and partially saturated porous media. Governing coupled equations for the displacement components and the fluid pressure are also obtained.